A 25 ～ 30 GHz low noise amplifier（ LNA） is designed for the application of 5 G communication technology in the millimeter wave band. In order to achieve high gain in the millimeter wave band

a three-stage circuit cascade structure is adopted

the first stage adopts a common source structure

the second and the third stages adopt a cascode structure

an interstage inductor is added between the common source tube and the common gate tube to eliminate the parasitic capacitance between the stages and suppress the output noise of the common gate. The circuit is optimized by adding a feedback network

and the E

n

-I

n

noise model is

used to perform noise analysis on the feedback network

so as to optimize LNA noise performance. Based on the TSMC 0. 13 μm CMOS process

the ADS software platform is used to simulate on LNA. The experimental results show that the performance is good in the 25～ 30 GHz band

S

11

2221=（ 25. 6 ± 0. 3） d B

NF =（ 2. 27～ 2. 77） d B.